Apparatus and method for filtering a bit stream and providing guard bands

ABSTRACT

An apparatus including: a communication unit configured to perform radio communication; and a control unit configured to perform control such that control information regarding a resource to which a filter for limiting a width of a guard band in a frequency band to be used in the radio communication is applied is transmitted to an external apparatus through the radio communication. The filter improves frequency use efficiency.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.16/067,762, filed Jul. 2, 2018, which is based on PCT filingPCT/JP2016/082166, filed Oct. 28, 2016, and claims priority to JapaneseApplication No. 2016-012196, filed Jan. 26, 2016, the entire contents ofeach are incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to an apparatus and a method.

BACKGROUND ART

In orthogonal frequency-division multiple access (OFDMA) andsingle-carrier frequency-division multiple access (SC-FDMA), which areadopted in Long Term Evolution (LTE)/LTE-Advanced (LTE-A), radioresources (e.g., resource blocks) are allocated to users withoutoverlap. There are cases in radio communication systems employing OFDMAor SC-FDMA in which some frequency bands among bands that are not usedin data transmission (Out-of-Bands or OOBs) are used as guard bands forreducing power leakage to adjacent systems. For example, PatentLiterature 1 discloses an example of a radio communication system inwhich part of a frequency band is used as a guard band.

In addition, a New Waveform technology has gained attention as onetechnology that is expected to improve frequency use efficiency amongradio access technologies (RATs) for the fifth generation (5G) mobilecommunication systems following LTE/LTE-A in recent years. The NewWaveform technology is a technology of cutting leaking power by applyingfilters to a transmission signal waveform and thereby improvingfrequency use efficiency. By applying the New Waveform technology,attenuation of signals of OOBs, more limitations on frequency bands tobe used as guard bands, and further improvement in frequency useefficiency are expected.

CITATION LIST Patent Literature

Patent Literature 1: JP 2015-46901A

DISCLOSURE OF INVENTION Technical Problem

On the other hand, in a case in which the New Waveform technology issupported, there are desirable cases in which a filter can be applied ina more preferable mode in accordance with a transmission/receptionenvironment or a use case.

Therefore, the present disclosure proposes an apparatus and a methodthat enable a filter for improving frequency use efficiency to beapplied in a more preferable mode.

Solution to Problem

According to the present disclosure, there is provided an apparatusincluding: a communication unit configured to perform radiocommunication; and a control unit configured to perform control suchthat control information regarding a resource to which a filter forlimiting a width of a guard band in a frequency band to be used in theradio communication is applied is transmitted to an external apparatusthrough the radio communication.

In addition, according to the present disclosure, there is provided anapparatus including: a communication unit configured to perform radiocommunication; and an acquisition unit configured to acquire controlinformation regarding a resource to which a filter for limiting a widthof a guard band in a frequency band to be used in the radiocommunication is applied from an external apparatus through the radiocommunication.

In addition, according to the present disclosure, there is provided anapparatus including: a communication unit configured to perform radiocommunication; and a control unit configured to perform control suchthat, on a basis of control information regarding a resource to which afilter for limiting a width of a guard band in a frequency band to beused in the radio communication is applied, the filter is applied totransmission data and the transmission data to which the filter has beenapplied is transmitted to an external apparatus through the radiocommunication.

In addition, according to the present disclosure, there is provided amethod including: performing radio communication; and performingcontrol, by a processor, such that control information regarding aresource to which a filter for limiting a width of a guard band in afrequency band to be used in the radio communication is applied istransmitted to an external apparatus through the radio communication.

In addition, according to the present disclosure, there is provided amethod including: performing radio communication; and acquiring, by aprocessor, control information regarding a resource to which a filterfor limiting a width of a guard band in a frequency band to be used inthe radio communication is applied from an external apparatus throughthe radio communication.

In addition, according to the present disclosure, there is provided amethod including: performing radio communication; and performingcontrol, by a processor, such that, on a basis of control informationregarding a resource to which a filter for limiting a width of a guardband in a frequency band to be used in the radio communication isapplied, the filter is applied to transmission data and the transmissiondata to which the filter has been applied is transmitted to an externalapparatus through the radio communication.

Advantageous Effects of Invention

According to the present disclosure described above, an apparatus and amethod that enable a filter for improving frequency use efficiency to beapplied in a more preferable mode are provided.

Note that the effects described above are not necessarily limitative.With or in the place of the above effects, there may be achieved any oneof the effects described in this specification or other effects that maybe grasped from this specification.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is an explanatory diagram for explaining an overview of a NewWaveform technology.

FIG. 2 is an explanatory diagram for explaining an overview of a NewWaveform technology.

FIG. 3 is an explanatory diagram for explaining an example of aschematic configuration of a system according to an embodiment of thepresent disclosure.

FIG. 4 is a block diagram illustrating an example of a configuration ofa base station according to the embodiment.

FIG. 5 is a block diagram illustrating an example of a configuration ofa terminal apparatus according to the embodiment.

FIG. 6 is an explanatory diagram for explaining an example of a processperformed by a transmission apparatus that supports the New Waveformtechnology.

FIG. 7 is an explanatory diagram for explaining an example of a processperformed by a transmission apparatus that supports the New Waveformtechnology.

FIG. 8A is an explanatory diagram for explaining an example of a processperformed by a transmission apparatus that supports the New Waveformtechnology.

FIG. 8B is an explanatory diagram for explaining an example of a processperformed by a transmission apparatus that supports the New Waveformtechnology.

FIG. 9 is an explanatory diagram for explaining an example of a processperformed by a reception apparatus that supports the New Waveformtechnology.

FIG. 10 is an explanatory diagram for explaining an example of aconfiguration of a resource block.

FIG. 11 is an explanatory diagram for explaining an example of aconfiguration of a resource block.

FIG. 12 is an explanatory diagram for explaining an example of aconfiguration of a resource block.

FIG. 13 is a flowchart illustrating an example of a flow of a series ofprocesses relating to determination of a filter application unit.

FIG. 14 is a flowchart illustrating an example of a flow of a series ofprocesses relating to switching of a filter application unit.

FIG. 15 is a block diagram illustrating a first example of a schematicconfiguration of an eNB.

FIG. 16 is a block diagram illustrating a second example of theschematic configuration of the eNB.

FIG. 17 is a block diagram illustrating an example of a schematicconfiguration of a smartphone.

FIG. 18 is a block diagram illustrating an example of a schematicconfiguration of a car navigation apparatus.

MODE(S) FOR CARRYING OUT THE INVENTION

Hereinafter, (a) preferred embodiment (s) of the present disclosure willbe described in detail with reference to the appended drawings. In thisspecification and the appended drawings, structural elements that havesubstantially the same function and structure are denoted with the samereference numerals, and repeated explanation of these structuralelements is omitted.

Note that description will be provided in the following order.

1. Introduction

1.1. New Waveform technology

1.2. Technical problem

2. Configuration examples

2.1. Configuration example of system

2.2. Configuration example of base station

2.3. Configuration example of terminal apparatus

3. Technical features

4. Application examples

4.1. Application example regarding base station

4.2. Application example regarding terminal apparatus

5. Conclusion

1. INTRODUCTION

<1.1. New Waveform Technology>

First, an overview of a New Waveform technology will be described withreference to FIG. 1 and FIG. 2 . FIG. 1 and FIG. 2 are explanatorydiagrams for explaining an overview of the New Waveform technology.

In orthogonal frequency-division multiple access (OFDMA) andsingle-carrier frequency-division multiple access (SC-FDMA), which areadopted in Long Term Evolution (LTE) or LTE-Advanced (LTE-A), radioresources (e.g., resource blocks) are allocated to users withoutoverlap. FIG. 1 , for example, illustrates an example of a frequencydomain power spectrum of transmission signals in a case in which OFDMAis applied. In FIG. 1 , the horizontal axis represents frequency bandsin a subcarrier and the vertical axis represents levels of transmissionpower.

In the waveforms of the transmission signal illustrated in FIG. 1 , thefrequency band indicated by reference numeral W11 represents a frequencyband used in data transmission (excluding NULL subcarriers), andfrequency bands other than that are Out-of-Bands (OOBs) not used in datatransmission. In addition, there are cases in which, among the OOBs, atleast some frequency bands are provided as a guard band for reducingpower leaking to an adjacent system. In a case in which no guard band isprovided, for example, even in a case in which power of about −10 dB isset in a subcarrier with maximum power among the OOBs, power up toapproximately −20 dB to −30 dB can be attenuated by providing guardbands.

By providing guard bands at both sides of a frequency band used in datatransmission in LTE/LTE-A by using the above-described mechanism,interference due to power leaking to an adjacent system can be reduced.

Meanwhile, there are cases in which the guard bands cause frequency useefficiency to deteriorate because some of the frequency bands are usedas unused bands (i.e., the bands are not used in data transmission). Asa specific example, in a case in which a channel width is 20 MHz, bandsof approximately 2 MHz (1 MHz for one side) are allocated as guardbands, and frequency use efficiency decreases by about 10% in this case.

Thus, the New Waveform technology has gained attention as one technologythat is expected to improve frequency use efficiency among radio accesstechnologies (RATs) for the fifth generation (5G) mobile communicationsystems following LTE/LTE-A. The New Waveform technology is a technologyof cutting leaking power by applying a filter to a transmission signalwaveform and thereby improving frequency use efficiency. For example,FIG. 2 illustrates an example of a frequency domain power spectrum ofthe transmission signal illustrated in FIG. 1 in a case in which a DolphShebychev filter is applied to the transmission signal. Note that thehorizontal axis and the vertical axis of FIG. 2 represent the same asthose in the example illustrated in FIG. 1 . In addition, in FIG. 2 ,the waveform of the transmission signal before the application of thefilter (i.e., the waveform illustrated in FIG. 1 ) is also presented.

As indicated by the waveform of the transmission signal after the filterapplication in FIG. 2 , it is ascertained that power decreases in theOOBs due to the filter application. In this manner, by applying the NewWaveform technology (i.e., applying the filter to the transmissionsignal), attenuation of signals of the OOBs, more limitations on thefrequency band widths to be used as guard bands, and further improvementin frequency use efficiency are expected.

Note that, if the frequency band widths to be used as the guard bandscan be further limited, the type of filter to be applied to thetransmission signal is not necessarily limited to the Dolph Chebyshevfilter illustrated in FIG. 2 . As a specific example, there are cases inwhich a so-called Nyquist filter such as a root-raised-cosine filter isapplied as a filter for realizing the New Waveform technology. Inaddition, a filter applied to the transmission signal is not necessarilylimited to a single filter, and a filter to be applied may be adaptivelyselected from a plurality of filters. For example, the above-describedDolph Chebyshev filter or root-raised-cosine filter may be selectivelyapplied depending on a situation. Note that, in a case in which it issimply described as a “filter” in the following description, it isassumed to indicate a filter for further limiting frequency band widthsto be used as guard bands, like the above-described filter unlessspecified otherwise.

The overview of the New Waveform technology has been described abovewith reference to FIG. 1 and FIG. 2 .

<1.2. Technical Problem>

Next, a technical problem according to an embodiment of the presentdisclosure will be described.

As described above, the New Waveform technology enables power leaking tothe OOBs to be further reduced by applying the filter (e.g., a DolphChebyshev filter) to the transmission signal. When the New Waveformtechnology is supported, it is desirable to apply a filter in a morepreferable mode in accordance with a transmission/reception environmentor a use case. In particular, when the above-described filter isapplied, for example, there are cases in which transmission/receptionprocessing amounts or characteristics of a filter-applied signal differdepending on whether the filter is applied with a series of resourceelements in one unit or the filter is applied with the resource elementsin finer units. Thus, for example, a determination method of a unit towhich a filter is applied and a method of transmitting the determinedunit to another apparatus are important matters to be discussed forsupporting the New Waveform technology.

Therefore, in description of the present disclosure, in particular, adetermination method of a unit to which a filter is applied and atransmission method of the unit will be focused on as an example of amechanism for applying a filter for improving frequency use efficiencyin a more preferable mode.

2. CONFIGURATION EXAMPLES

<2.1. Configuration Example of System>

First, an example of a schematic configuration of a system 1 accordingto an embodiment of the present disclosure will be described withreference to FIG. 3 . FIG. 3 is an explanatory diagram for explaining anexample of a schematic configuration of the system 1 according to theembodiment of the present disclosure. As illustrated in FIG. 3 , thesystem 1 includes radio communication apparatuses 100 and terminalapparatuses 200. Here, the terminal apparatuses 200 are also calledusers. The users can also be called UE. The radio communicationapparatus 100C is also called UE-Relay. Here, UE may be UE defined inLTE or LTE-A, and the UE-Relay may be Prose UE to Network Relaydiscussed in the 3GPP, or may more generally mean a communicationdevice.

(1) Radio Communication Apparatus 100

Each of the radio communication apparatuses 100 is an apparatus thatprovides radio communication services to apparatuses under its control.The radio communication apparatus 100 is a base station of a cellularsystem (or mobile communication system). The base station 100A performsradio communication with an apparatus (e.g., the terminal apparatus200A) located in a cell 10A of the base station 100A. For example, thebase station 100A transmits a downlink signal to the terminal apparatus200A, and receives an uplink signal from the terminal apparatus 200A.

The base station 100A and another base station are logically connectedthrough, for example, an X2 interface and can transmit and receivecontrol information and the like to and from each other. In addition,the base station 100A and a so-called core network (illustration ofwhich is omitted) are logically connected through, for example, an S1interface and can transmit and receive control information and the liketo and from each other. Note that communication between the apparatusescan be physically relayed by various apparatuses.

Here, the radio communication apparatus 100A illustrated in FIG. 3 is amacro cell base station, and a cell 10A is a macro cell. Meanwhile, theradio communication apparatuses 100B and 100C are master devices eachoperating small cells 10B and 10C. As an example, the master device 100Bis a fixedly installed small cell base station. The small cell basestation 100B establishes each of a radio backhaul link with the macrocell base station 100A and an access link with one or more terminalapparatuses (e.g., the terminal apparatus 200B) within the small cell10B. Note that the radio communication apparatus 100B may be a relaynode defined in the 3GPP. The master device 100C is a dynamic accesspoint (AP). The dynamic AP 100C is a mobile device dynamically operatingthe small cell 10C. The dynamic AP 100C establishes each of a radiobackhaul link with the macro cell base station 100A and an access linkwith one or more terminal apparatuses (e.g., the terminal apparatus200C) within the small cell 10C. The dynamic AP 100C may be, forexample, a terminal apparatus in which hardware or software that canoperate as a base station or a radio access point is mounted. The smallcell 10C of that case is a dynamically formed local network (localizednetwork/virtual cell).

The cell 10A may be managed in accordance with an arbitrary radiocommunication scheme, for example, LTE, LTE-A (LTE-Advanced), GSM(registered trademark), UMTS, W-CDMA, CDMA 200, WiMAX, WiMAX 2, IEEE802.16, or the like.

Note that a small cell is a concept in which the cell can be disposed tooverlap or not to overlap a macro cell and include various kinds ofcells smaller than the macro cell (e.g., a femto cell, a nano cell, apico cell, a micro cell, and the like). In a certain example, a smallcell is managed by a dedicated base station. In another example, a smallcell is managed when a terminal serving as a master device temporarilyoperates as a small cell base station. A so-called relay node can alsobe deemed as a form of a small cell base station. A radio communicationapparatus functioning as a master station of a relay node is also calleda donor base station. A donor base station may mean a DeNB in LTE ormore generally mean a master station of a relay node.

(2) Terminal Apparatus 200

The terminal apparatus 200 can perform communication in a cellularsystem (or mobile communication system). The terminal apparatus 200performs radio communication with a radio communication station (e.g.,the base station 100A, or the master apparatus 100B or 100C) of thecellular system. For example, the terminal apparatus 200A receives adownlink signal from the base station 100A, and transmits an uplinksignal to the base station 100A.

(3) Supplement

Although the schematic configuration of the system 1 has been introducedabove, the present technology is not limited to the example illustratedin FIG. 3 . As a configuration of the system 1, for example, aconfiguration with no master device, Small Cell Enhancement (SCE), aheterogeneous network (HetNet), a machine type communication (MTC)network, or the like can be adopted.

<2.2. Configuration Example of Base Station>

Next, the configuration of the base station 100 according to anembodiment of the present disclosure will be described with reference toFIG. 4 . FIG. 4 is a block diagram illustrating the example of theconfiguration of the base station 100 according to an embodiment of thepresent disclosure. According to FIG. 4 , the base station 100 includesan antenna unit 110, a radio communication unit 120, a networkcommunication unit 130, a storage unit 140, and a processing unit 150.

(1) Antenna Unit 110

The antenna unit 110 radiates signals output by the radio communicationunit 120 out into space as radio waves. In addition, the antenna unit110 converts radio waves in the space into signals, and outputs thesignals to the radio communication unit 120.

(2) Radio Communication Unit 120

The radio communication unit 120 transmits and receives signals. Forexample, the radio communication unit 120 transmits a downlink signal toa terminal apparatus, and receives an uplink signal from a terminalapparatus.

(3) Network Communication Unit 130

The network communication unit 130 transmits and receives information.For example, the network communication unit 130 transmits information toother nodes, and receives information from other nodes. For example, theother nodes include another base station and a core network node.

(4) Storage Unit 140

The storage unit 140 temporarily or permanently stores a program andvarious data for operation of the base station 100.

(5) Processing Unit 150

The processing unit 150 provides various functions of the base station100. The processing unit 150 includes a communication processing unit151 and a notification unit 153. Further, the processing unit 150 mayfurther include other components in addition to these components. Thatis, the processing unit 150 may perform operations in addition tooperations of these components.

Note that operations of the communication processing unit 151 and thenotification unit 153 will be described below in detail.

<2.3. Configuration Example of Terminal Apparatus>

Next, an example of the configuration of the terminal apparatus 200according to an embodiment of the present disclosure will be describedwith reference to FIG. 5 . FIG. 5 is a block diagram illustrating theexample of the configuration of the terminal apparatus 200 according toan embodiment of the present disclosure. As illustrated in FIG. 5 , theterminal apparatus 200 includes an antenna unit 210, a radiocommunication unit 220, a storage unit 230, and a processing unit 240.

(1) Antenna Unit 210

The antenna unit 210 radiates signals output by the radio communicationunit 220 out into space as radio waves. In addition, the antenna unit210 converts radio waves in the space into signals, and outputs thesignals to the radio communication unit 220.

(2) Radio Communication Unit 220

The radio communication unit 220 transmits and receives signals. Forexample, the radio communication unit 220 receives a downlink signalfrom a base station, and transmits an uplink signal to a base station.

(3) Storage Unit 230

The storage unit 230 temporarily or permanently stores a program andvarious data for operation of the terminal apparatus 200.

(4) Processing Unit 240

The processing unit 240 provides various functions of the terminalapparatus 200. For example, the processing unit 240 includes aninformation acquisition unit 241, a communication processing unit 243,and a notification unit 245. Note that the processing unit 240 mayfurther include a structural element other than these structuralelements. That is, the processing unit 240 may perform operation otherthan the operation of these structural elements.

Note that operations of the information acquisition unit 241, thecommunication processing unit 243, and the notification unit 245 will bedescribed below in detail.

3. TECHNICAL FEATURES

Next, technical features of the present disclosure will be described.

(1) Processes by Each Apparatus

(a) Processes by Transmission Apparatus

First, examples of processes performed by a transmission apparatus thatsupports the New Waveform technology will be described with referenceFIG. 6 , FIG. 7 , and FIG. 8A. FIG. 6 , FIG. 7 , and FIG. 8A areexplanatory diagrams for explaining examples of processes performed bythe transmission apparatus that supports the New Waveform technology. Abit stream (e.g., a transport block) of each user is processed asillustrated in FIG. 6 , FIG. 7 , and FIG. 8A. On the bit stream of eachuser, several processes, for example, cyclic redundancy check (CRC)coding, forward error correction (FEC) coding, rate matching, andscrambling/interleaving) are performed as illustrated in FIG. 6 , andthen modulation is performed. Then, on the modulated bit stream, layermapping, power allocation, precoding, resource element mapping areperformed, and bit streams of each of antenna elements are output asillustrated in FIG. 7 .

The bit streams of each of the antennas are divided into units decidedon the basis of a size (in other words, the number of resources) in atleast any of a frequency direction and a time direction having resourceelements as minimum units. At this time, each of the units includes oneor more resource elements. In addition, each of the units is subjectedto a filtering process for further limiting frequency bandwidths to beused as guard bands. Note that the units are units to which a filter isapplied (which will also be referred to as “filter application units”below). In the example illustrated in FIG. 8A, for example, each ofresource elements constituting a resource block is divided into B unitsfrom 0 to B−1, and a process relating to filter application is executedon each of the units. Specifically, the bit stream of each antenna issubjected to a filtering process after an IFFT or IDFT process isperformed on each unit. Note that a determination method of a filterapplication unit will be separated described below in detail.

Then, the bit streams of each of the units that have undergone thefiltering process are added together, guard intervals are added theretoif necessary, conversion from digital to analog/radio frequency (RF) orthe like is performed thereon, and then the results are transmitted fromeach of the antennas.

Note that each of the above-described processes performed by thetransmission apparatus may be executed on the basis of control by apredetermined control unit (e.g., the PHY configuration controller inthe drawing).

In addition, although the example in which the filter is applied to thebit streams (i.e., transmission signals) of each of the antennas in thetime domain has been described above, a filter may be applied thereto inthe frequency domain. For example, FIG. 8B is an explanatory diagram fordescribing an example of a process performed by the transmissionapparatus that supports the New Waveform technology, and the example inwhich a filter is applied to bit streams of each of antennas in thefrequency domain is shown. In this case, the filtering process may beperformed on each of units of the bit streams of each of the antennasand then the IFFT or IDFT process may be performed on thefiltering-processed units as illustrated in FIG. 8B. Note that thefollowing processes are similar to the case in which the filter isapplied in the time domain as illustrated in FIG. 8A.

(b) Processes by Reception Apparatus

Next, an example of processes performed by a reception apparatus thatsupports the New Waveform technology will be described with reference toFIG. 9 . FIG. 9 is an explanatory diagram for explaining the example ofthe processes performed by the reception apparatus that supports the NewWaveform technology.

As illustrated in FIG. 9 , processes of conversion from RF/analog todigital, zero padding, a discrete Fourier transform (DFT)/fast Fouriertransform (FFT), down sampling, equalization and decoding, and the likeare performed on a signal received by each of antennas. Note that, inthe reception apparatus that supports the New Waveform technology, theinverse process of the filtering process based on the New Waveformtechnology is performed at the time of equalization and decoding. As aresult, bit streams ((e.g., transport blocks) for respective users areobtained. Note that more details of the reception process will bedescribed below along with description of a reception signal.

In addition, each of the above-described processes performed by thereception apparatus may be executed on the basis of control by apredetermined control unit (e.g., the PHY configuration controller inthe drawing).

(2) Transmission Signal and Reception Signal Next, a transmission signaland a reception signal in a case in which the New Waveform technology issupported will be described. Note that, in the present description, amulti-cell system of a heterogeneous network (HetNet), Small CellEnhancement (SCE), or the like is assumed. In addition, in the presentdescription, an index corresponding to a subcarrier, a symbol, a sample,a slot, and an index corresponding to a subframe will not be describedunless specified otherwise.

A reception apparatus that is a transmission target is set to u, and thenumber of transmission antennas of a transmission apparatus thattransmits a signal to the reception apparatus is set to N_(t). Note thateach of the transmission antennas is also called a “transmission antennaport.” Here, a transmission signal to the reception apparatus u can beexpressed in a vector format as indicated by the following (Formula 1).

[Math.  1]                                                                                (Formula  1)$\begin{matrix}{x_{u} = \begin{bmatrix}x_{u,0,0} & \ldots & x_{u,0,{N + N_{GI} + N_{f} - 2}} \\\vdots & \ddots & \vdots \\x_{u,{N_{t} - 1},0} & \ldots & x_{u,{N_{t} - 1},{N + N_{GI} + N_{f} - 2}}\end{bmatrix}^{T}} \\{= {\sum\limits_{b = 0}^{B - 1}{\Omega_{u,b}G_{u,b}F^{H}P_{u,b}W_{u,b}S_{u,b}}}} \\{= {\sum\limits_{b = 0}^{B - 1}\left( {{\underset{\underset{\Omega_{u,b}{\lbrack{{({N + N_{f} + N_{GI} - 1})} \times {({N + N_{f} - 1})}}\rbrack}}{︸}}{\begin{bmatrix}I_{N + N_{f} - 1} \\0 \\\vdots \\\vdots \\\vdots \\0\end{bmatrix}}\underset{\underset{G_{u,b}{\lbrack{{({N + N_{f} - 1})} \times N}\rbrack}}{︸}}{\begin{bmatrix}{g_{u,b}(0)} & 0 & \ldots & 0 \\\vdots & {g_{u,b}(0)} & \ddots & \vdots \\{g_{u,b}\left( {N_{f} - 1} \right)} & \vdots & \ddots & 0 \\0 & {g_{u,b}\left( {N_{f} - 1} \right)} & \ddots & {g_{u,b}(0)} \\\vdots & \vdots & \ddots & \vdots \\0 & 0 & \ldots & {g_{u,b}\left( {N_{f} - 1} \right)}\end{bmatrix}}{\underset{\underset{F^{H}{\lbrack{N \times N}\rbrack}}{︸}}{\begin{bmatrix}e^{{({{- i}\; 2\;{\pi/N}})} \cdot 0} & e^{{({{- i}\; 2\;{\pi/N}})} \cdot 0} & \ldots & e^{{({{- i}\; 2\;{\pi/N}})} \cdot {({N - 1})} \cdot 0} \\e^{{({{- i}\; 2\;{\pi/N}})} \cdot 0} & e^{{({{- i}\; 2\;{\pi/N}})} \cdot 1} & \ldots & e^{{({{- i}\; 2\;{\pi/N}})} \cdot {({N - 1})} \cdot 1} \\\vdots & \vdots & \ddots & \vdots \\\vdots & \vdots & \ddots & \vdots \\\vdots & \vdots & \ddots & \vdots \\e^{{({{- i}\; 2\;{\pi/N}})} \cdot 0} & e^{{({{- i}\; 2\;{\pi/N}})} \cdot {({N - 1})}} & \ldots & e^{{({{- i}\; 2\;{\pi/N}})} \cdot {({N - 1})} \cdot {({N - 1})}}\end{bmatrix}}}^{H}} +} \right.}} \\{\left. \left\lbrack {\underset{\underset{P_{u,b}{\lbrack{N_{t} \times N_{t}}\rbrack}}{︸}}{\begin{bmatrix}P_{u,b,0,0} & \ldots & P_{u,b,{N_{t} - 1},0} \\\vdots & \ddots & \vdots \\P_{u,b,0,{N_{t} - 1}} & \ldots & P_{u,b,{N_{t} - 1},{N_{t} - 1}}\end{bmatrix}}\underset{\underset{W_{u,b}{\lbrack{N_{SS} \times N_{t}}\rbrack}}{︸}}{\begin{bmatrix}W_{u,b,0,0} & \ldots & W_{u,b,0,{N_{SS} - 1}} \\\vdots & \ddots & \vdots \\W_{u,b,{N_{t} - 1},0} & \ldots & W_{u,b,{N_{t} - 1},{N_{SS} - 1}}\end{bmatrix}}\underset{\underset{S_{u,b}{\lbrack{N_{SS} \times N}\rbrack}}{︸}}{\begin{bmatrix}S_{u,b,0,0} & \ldots & S_{u,b,0,{N - 1}} \\\vdots & \ddots & \vdots \\S_{u,b,{N_{SS} - 1},0} & \ldots & S_{u,b,{N_{SS} - 1},{N - 1}}\end{bmatrix}}} \right\rbrack^{T} \right),}\end{matrix}$

In the above-described (Formula 1), N denotes an FFT size length. Inaddition, N_(f) denotes a filter length, and B denotes the number ofsub-bands to which a filter is applied. In addition, N_(t) denotes thenumber of transmission antennas, and N_(s), denotes the number ofspatial transmission streams. In addition, the vector S_(u,b) denotes aspatial stream signal of the reception apparatus u in a sub-band b. Eachelement of the vector S_(u,b) basically corresponds to a digitalmodulation symbol of PSK, QAM, or the like. Here, for example, ifsub-band b=0 is assumed to be a set of subcarriers from 0^(th) tok−1-th, the condition indicated by the following (Formula 2) is assumedto be satisfied.

$\begin{matrix}\left\lbrack {{Math}.\mspace{14mu} 2} \right\rbrack & \; \\{{S_{u,0,n_{SS},k}\text{∼}S_{u,0,n_{SS},{N - 1}}} = {0\left( {0 \leq n_{ss} \leq {N_{SS} - 1}} \right)}} & \left( {{Formula}\mspace{14mu} 2} \right)\end{matrix}$

W_(u,b) denotes a precoding matrix for the sub-band b of the receptionapparatus u. In addition, P_(u,b) denotes a power allocation coefficientmatrix for the sub-band b of the reception apparatus u. Note that eachelement of the matrix P_(u,b) is desirably a positive real number. Inaddition, the matrix P_(u,b) may be a so-called diagonal matrix (i.e., amatrix of which elements other than the diagonal elements are 0). Thematrix P_(u,b) is expressed by the following (Formula 3), for example.

$\begin{matrix}\left\lbrack {{Math}.\mspace{14mu} 3} \right\rbrack & \; \\{P_{u,b} = \begin{bmatrix}P_{u,b,0,0} & 0 & \ldots & 0 \\0 & P_{u,b,1,1} & \ddots & \vdots \\\vdots & \ddots & \ddots & 0 \\0 & \ldots & 0 & P_{u,b,{N_{t} - 1},{N_{t} - 1}}\end{bmatrix}} & \left( {{Formula}\mspace{14mu} 3} \right)\end{matrix}$

Note that, if adaptive power allocation for a spatial stream is notperformed, a scalar value P_(u,b) may be used instead of the matrixP_(u,b).

The vector F denotes an FFT matrix having a size N, and the vectorG_(u,b) denotes a linear convolution matrix of a filter applied to thesub-band b of the reception apparatus u. In addition, the vector Ω_(u,b)corresponds to insertion of a guard interval (GI). I_(N) in Ω_(u,b)denotes a unit matrix with a size N, and N_(GI) denotes a length of aguard interval.

In addition, if a reception signal received by the reception apparatus uin a case in which a transmission signal of a transmission antenna#n_(t) is received by a reception antenna #n_(r) is assumed to ber_(u,nt,nr), the reception signal r_(u,nt,nr) is expressed by thefollowing (Formula 4).

     [Math.  4]                                       (Formula  4)$\begin{matrix}{r_{u,n_{t},n_{r}} = \begin{bmatrix}r_{u,n_{t},n_{r},0} \\\vdots \\r_{u,n_{t},n_{r},{N + N_{f} + N_{GI} + L_{h} - 3}}\end{bmatrix}} \\{= {{h_{u,n_{t},n_{r}}x_{u,n_{t}}} + n_{u,n_{r}}}} \\{= \underset{\underset{h_{u}{\lbrack{{({N + N_{f} + N_{GI} + L_{h} - 2})} \times {({N + N_{f} + N_{GI} - 1})}}\rbrack}}{︸}}{\begin{bmatrix}{h_{u,n_{t},n_{r}}(0)} & 0 & \ldots & 0 \\\vdots & {h_{u,n_{t},n_{r}}(0)} & \ddots & \vdots \\{h_{u,n_{t},n_{r}}\left( {L_{h} - 1} \right)} & \vdots & \ddots & 0 \\0 & {h_{u,n_{t},n_{r}}\left( {L_{h} - 1} \right)} & \ddots & {h_{u,n_{t},n_{r}}(0)} \\\vdots & \vdots & \ddots & \vdots \\0 & 0 & \ldots & {h_{u},n_{t},{n_{r}\left( {L_{h} - 1} \right)}}\end{bmatrix}}} \\{\underset{\underset{x_{u,n_{t}}{\lbrack{{({N + N_{f} + N_{GI} - 1})} \times 1}\rbrack}}{︸}}{\begin{bmatrix}x_{u,n_{t},0} \\x_{u,n_{t},1} \\\vdots \\\vdots \\\vdots \\x_{u,n_{t},{N + N_{f} + N_{CP} - 1}}\end{bmatrix}} + \underset{\underset{n_{u,n_{r}}{\lbrack{{({N + N_{f} + N_{GI} + L_{h} - 2})} \times 1}\rbrack}}{︸}}{\begin{bmatrix}n_{u,n_{r},0} \\n_{u,n_{r},1} \\\vdots \\\vdots \\\vdots \\n_{u,n_{r},{N + N_{f} + N_{CP} + L_{h} - 3}}\end{bmatrix}}}\end{matrix}$

Note that, in the above-described (Formula 4), L_(h) denotes the numberof transmission line paths. In addition, the matrix h_(u,nt,nr) denotesa channel response matrix between the transmission antenna n_(t) and thereception antenna n_(r). Note that each element of the matrixh_(u,nt,nr) is basically a complex number. In addition, the vectorn_(u,nr) denotes noise of the reception antenna n_(r) of the receptionapparatus u. Note that the noise n_(u,nr) includes, for example, thermalnoise or interference from a system other than the system that is theobject of the present disclosure. Note that average noise power isdenoted by σ_(n,u) ².

In addition, in the case in which the New Waveform technology issupported, the above-described reception signal r_(u,nt,nr) correspondsto a signal to which the above-described filter G_(u,b) has beenapplied. Thus, in the course of performing a DFT/FFT, and equalizationand decoding on the reception signal r_(u,nt,nr), the inverse processesof the above-described processes to which the filter G_(u,b) is appliedare performed.

Specifically, a signal length (i.e., the number of sample symbols) ofthe reception signal r_(u,nt,nr) increases by a filter length of thefilter G_(u,b) in accordance with the above-described application of thefilter G_(u,b). Thus, it is necessary for the reception apparatus u atthe time of the DFT/FFT process (i.e., during OFDM decoding) performedon the reception signal r_(u,nt,nr) to consider a size of the filterlength and a size of a delay of a channel in addition to the size of theIFFT at the time of the transmission process. Thus, the receptionapparatus u adjusts the signal length of the reception signalr_(u,nt,nr) to be 2N by executing, for example, zero padding from theend of the reception signal r_(u,nt,nr).

Next, the reception apparatus u converts the reception signalr_(u,nt,nr) that has undergone zero padding into a signal of thefrequency domain by applying the DFT/FFT of the size 2N thereto andapplies ½ down sampling to the converted signal. Through this process,the signal length of the reception signal that has been adjusted to 2Nby performing zero padding thereon is adjusted to N through ½ downsampling.

In addition, the reception apparatus u can decode a transmitted spatialstream signal by executing frequency domain equalization on thedown-sampled reception signal. For example, a minimum mean square error(MMSE) weight is conventionally created in consideration of the channelmatrix h_(u,nr,nr), the precoding matrix W_(u,b), and the noise powerσ_(u,n) ². With respect to this, in the case in which the New Waveformtechnology is supported like the present disclosure, an equalizationweight is created further in consideration of the filter matrix Goapplied in the transmission signal process in addition to the above.

The transmission signal and the reception signal in the case in whichthe New Waveform technology is supported have been described above.

(3) Filter Application Unit

Next, a filter application unit will be described in detail withreference to FIG. 10 to FIG. 12 . As described above, a filterapplication unit (i.e., the above-described unit) for further limiting afrequency bandwidth to be used as a guard band is determined on thebasis of a size (i.e., the number of resources) in at least one of afrequency direction and a time direction with a resource element as aminimum unit. More precisely, the filter application unit is determinedby setting a minimum time-frequency unit used in transmission as aminimum unit to which a filter is applied.

In the case of LTE/LTE-A, for example, one symbol of one subcarrier isdefined as a resource element, and a filter application unit isdetermined by setting the resource element as a minimum unit. Note that,in LTE/LTE-A, as a configuration of a resource block (i.e., a method ofdividing a resource block into resource elements), the three casesillustrated in FIG. 10 to FIG. 12 are assumed, and sizes of resourceelements (i.e., a band of one subcarrier and a symbol length of onesymbol) differ in each of the cases. FIG. 10 to FIG. 12 are explanatorydiagrams for explaining examples of configurations of resource blocks.

FIG. 10 illustrates an example of a configuration of a resource block,for example, in a case in which the number of symbols is set to 7 andthe number of subcarriers is set to 12. In this case, the band of onesubcarrier is 15 kHz, and the symbol length of one symbol is 2208 Ts or2192 Ts when Ts=1/30720 [ms]. That is, in the example illustrated inFIG. 10 , a minimum unit to which a filter is applied is 15 kHz×2208 Ts(in the case of #0 symbol).

In addition, FIG. 11 illustrates an example of a configuration of aresource block in a case in which the number of symbols is set to 6 andthe number of subcarriers is set to 12. In this case, the band of onesubcarrier is 15 kHz and the symbol length of one symbol is 2560 Ts.That is, in the example illustrated in FIG. 11 , a minimum unit to whicha filter is applied is 15 kHz×2560 Ts.

In addition, FIG. 12 illustrates an example of a configuration of aresource block in a case in which the number of symbols is set to 3 andthe number of subcarriers is set to 24. In this case, the band of onesubcarrier is 7.5 kHz and the symbol length of one symbol is 5120 Ts.That is, in the example illustrated in FIG. 12 , a minimum unit to whicha filter is applied is 7.5 kHz×5120 Ts.

Note that the above-described examples are merely examples, and aconfiguration of the filter application unit is not necessarily limitedto the examples described with reference to FIG. 10 to FIG. 12 as longas a minimum time-frequency unit used in transmission is determined tobe a minimum unit to which a filter is applied. For example, a case inwhich a plurality of sub-symbols are defined by further dividing onesymbol can be assumed depending on a modulation scheme. In this case,for example, one subcarrier×one sub-symbol may be set as a minimum unitto which a filter is applied.

(4) Filter Application Unit Determination Method

Successively, an example of a method of determining a filter applicationunit will be described. With respect to a filter application unit, acase in which a predetermined application unit thereof is fixedly used(i.e., a fixed case) and a case in which a predetermined applicationunit thereof is changeable in accordance with a situation (i.e., avariable case) are exemplified. In addition, as the cases in which afilter application unit is variable, a case in which the applicationunit is semi-statically determined and a case in which the applicationunit is dynamically determined are exemplified. Thus, the case in whicha filter application unit is fixed, the case in which the filterapplication unit is semi-statically determined, and the case in whichthe filter application unit is dynamically determined will be eachdescribed in detail.

(a) Case in which Filter Application Unit is Fixed

First, the case in which a filter application unit is fixed will bedescribed. In the case in which a filter application unit is fixed, thefilter application unit is determined as a specification (e.g., acommunication protocol, etc.), and a base station and a terminalapparatus apply filters to transmission signals in each unit on thebasis of the specification. For example, the following Table 1 showsexamples of settings (specifications) of filter application units in thecase of LTE. Note that, in Table 1, “Application Unit” represents unitsthat are filter application targets, i.e., filter application units.

TABLE 1 Filter application units 1 Subcarrier 1 Symbol Band Type bandwidth length width Application Unit  0  15 kHz 2208T_(s) or 1.4 MHz 72Subcarrier × 1 Symbol (or Subsymbol) 2192T_(s)  1  15 kHz 2560T_(s) 1.4MHz 72 Subcarrier × 1 Symbol (or Subsymbol)  2 7.5 kHz 5120T_(s) 1.4 MHz144 Subcarrier × 1 Symbol (or Subsymbol)  3  15 kHz 2208T_(s) or   3 MHz180 Subcarrier × 1 Symbol (or Subsymbol) 2192T_(s)  4  15 kHz 2560T_(s)  3 MHz 180 Subcarrier × 1 Symbol (or Subsymbol)  5 7.5 kHz 5120T_(s)  3 MHz 360 Subcarrier × 1 Symbol (or Subsymbol)  6  15 kHz 2208T_(s) or  5 MHz 300 Subcarrier × 1 Symbol (or Subsymbol) 2192T_(s)  7  15 kHz2560T_(s)   5 MHz 300 Subcarrier × 1 Symbol (or Subsymbol)  8 7.5 kHz5120T_(s)   5 MHz 600 Subcarrier × 1 Symbol (or Subsymbol)  9  15 kHz2208T_(s) or  10 MHz 600 Subcarrier × 1 Symbol (or Subsymbol) 2192T_(s)10  15 kHz 2560T_(s)  10 MHz 600 Subcarrier × 1 Symbol (or Subsymbol) 117.5 kHz 5120T_(s)  10 MHz 1200 Subcarrier × 1 Symbol (or Subsymbol) 12 15 kHz 2208T_(s) or  15 MHz 900 Subcarrier × 1 Symbol (or Subsymbol)2192T_(s) 13  15 kHz 2560T_(s)  15 MHz 900 Subcarrier × 1 Symbol (orSubsymbol) 14 7.5 kHz 5120T_(s)  15 MHz 1800 Subcarrier × 1 Symbol (orSubsymbol) 15  15 kHz 2208T_(s) or  20 MHz 1200 Subcarrier × 1 Symbol(or Subsymbol) 2192T_(s) 16  15 kHz 2560T_(s)  20 MHz 1200 Subcarrier ×1 Symbol (or Subsymbol) 17 7.5 kHz 5120T_(s)  20 MHz 2400 Subcarrier × 1Symbol (or Subsymbol) 18  15 kHz 2208T_(s), 1.4, 3, 5, 12 Subcarrier × 1Symbol (or Subsymbol) 2192T_(s) or 10, 15 or 2560T_(s)  20 MHz 19 7.5kHz 5120T_(s) 1.4, 3, 5, 24 Subcarrier × 1 Symbol (or Subsymbol) 10, 15or  20 MHz 20 7.5 or 15 kHz 2208T_(s), 1.4, 3, 5, 1 Subcarrier × 1Symbol (or Subsymbol) 2192T_(s) or 10, 15 or 2560T_(s)  20 MHz

Note that the examples denoted by Type 0 to Type 17 in theabove-described Table 1 show examples of settings in a case in which afilter is applied to each symbol (or each sub-symbol) through abandwidth. Meanwhile, the examples denoted by Type 18 to Type 20 showexamples in a case in which a filter is applied in a frequency directionin finer units than in the examples denoted by Type 0 to Type 17.

Note that information representing a filter application unit as shown inTable 1 may be stored by each of the base station and the terminalapparatus in a readable storage area (e.g., the storage unit 140 and thestorage unit 230). In addition, as another example, the base station mayread the information representing the filter application unit from thepredetermined storage area and notify the terminal apparatus of theinformation regarding the application unit in accordance with the readresult.

(b) Case in which Filter Application Unit is Semi-Statically Determined

Next, the case in which a filter application unit is semi-staticallydetermined will be described. In the case in which a filter applicationunit is semi-statically determined, the base station and the terminalapparatus prescribe candidates for setting that can be taken as a filterapplication unit in advance. In addition, for example, the base stationdetermines a filter application unit among the candidates prescribed inadvance on the basis of a predetermined condition and notifies theterminal apparatus of information regarding the determined applicationunit (i.e., information regarding a resource to which the filter isapplied). Table 2 below shows, for example, an example of candidates forthe filter application unit.

TABLE 2 Filter application units Index Application Unit  0 1 Subcarrier× 1 Symbol (or Subsymbol)  1 12 Subcarrier × 1 Symbol (or Subsymbol)  224 Subcarrier × 1 Symbol (or Subsymbol)  3 72 Subcarrier × 1 Symbol (orSubsymbol)  4 144 Subcarrier × 1 Symbol (or Subsymbol)  5 180 Subcarrier× 1 Symbol (or Subsymbol)  6 300 Subcarrier × 1 Symbol (or Subsymbol)  7360 Subcarrier × 1 Symbol (or Subsymbol)  8 600 Subcarrier × 1 Symbol(or Subsymbol)  9 900 Subcarrier × 1 Symbol (or Subsymbol) 10 1200Subcarrier × 1 Symbol (or Subsymbol) 11 1800 Subcarrier × 1 Symbol (orSubsymbol) 12 2400 Subcarrier × 1 Symbol (or Subsymbol)

Note that the information representing the candidates for the filterapplication unit shown in Table 2 may be stored by each of the basestation and the terminal apparatus in a readable storage area (e.g., thestorage unit 140 and the storage unit 230). In addition, as anotherexample, the terminal apparatus may recognize the candidates for thefilter application unit when the base station notifies the terminalapparatus of the information representing the candidates for the filterapplication unit.

Next, determination criteria for determining a filter application unitwill be focused on. As determination criteria for determining a filterapplication unit, there are the following examples.

-   -   Bandwidth of the system    -   Feedback from the terminal apparatus on a communication quality    -   Retransmission request from the terminal apparatus    -   Position information of the terminal apparatus    -   Use application of the terminal apparatus (a request for a        communication quality from the terminal apparatus)    -   Request for switching of a filter application unit from the        terminal apparatus

Specifically, the base station determines a filter application unitwithin a bandwidth available for the system.

In addition, since the base station can recognize a channel condition onthe basis of feedback from the terminal apparatus on a communicationquality, the base station may determine a filter application unit inaccordance with a recognition result of the channel condition. As a morespecific example, in a case in which channel conditions aredeteriorating, a case in which the base station allocates frequencieswith channels in better conditions to the terminal apparatus is assumed.However, in such a situation in which channel conditions aredeteriorating, a case in which frequencies with channels in betterconditions are limited and the range of available frequencies isnarrower can be assumed. In such a case, the base station may causefrequencies to be allocated to the terminal apparatus to be narrower anddetermine a filter application unit in accordance with the frequencyallocation. Through such control, a decrease in throughput of theterminal apparatus can be suppressed, frequencies available for otherterminal apparatuses can be secured, and further improvement in thethroughput of the entire system can also be expected.

In addition, a case in which a filter application unit is determined onthe basis of a retransmission request from the terminal apparatus andposition information of the terminal apparatus is similar to the case inwhich a filter application unit is determined on the basis of feedbackfrom the terminal apparatus on a communication quality. In a case inwhich there is a retransmission request from the terminal apparatus, forexample, a possibility of a channel condition deteriorating isconceivable. In addition, there are cases in which a propagationdistance between the base station and the terminal apparatus becomesfarther depending on a position of the terminal apparatus, and in such acircumstance, there is a possibility of a channel conditiondeteriorating. In such a case in which a channel condition isdeteriorating as described above, the base station may cause frequenciesallocated to the terminal apparatus to be narrower and determine afilter application unit in accordance with the frequency allocation.

In addition, a case in which communication qualities requested by theterminal apparatus differ depending on use applications of the terminalapparatus can be assumed. For example, there are cases in whichfrequency bands allocated to the terminal apparatus may be relativelynarrower as in a case in which a packet size may be small or a case inwhich latency is tolerable depending on use applications of the terminalapparatus. On the other hand, in a case in which a bucket size is largeror a case in which low latency communication is required, there arecases in which it is desirable to allocate a wider frequency band to theterminal apparatus. Assuming such a situation, for example, the basestation may determine a bandwidth of a frequency to be allocated to theterminal apparatus in accordance with a request for a communicationquality (e.g., Quality-of-Service or QoS) from the terminal apparatusand determine a filter application unit in accordance with thebandwidth.

In addition, in a case in which the base station receives a request forswitching of a filter application unit from the terminal apparatus, thebase station may switch a filter application unit in accordance with therequest. In this case, for example, the base station may allocate achannel to the terminal apparatus in accordance with a condition of achannel with the terminal apparatus, a communication quality requestedfrom the terminal apparatus, or the like, and determine a filterapplication unit in accordance with the allocation.

Note that, in a case in which a filter application unit is determined(switched), the base station notifies the terminal apparatus ofinformation regarding the determined application unit. Note that, as theinformation of which the base station notifies the terminal, forexample, information directly representing a filter application unit(i.e., the number of subcarriers, the number of symbols, or the like towhich a filter is applied), an index value associated with theapplication unit, and the like are exemplified.

Next, methods of the base station notifying the terminal apparatus ofthe information representing the filter application unit will befocused. As methods of notifying of the information representing thefilter application unit, for example, there are the following examples.

-   -   Notifying as part of RRC signaling (RRC Message)    -   Notifying as part of system information    -   Notifying as part of downlink control information (DCI)

With the above-described configuration, a filter application unit can beswitched in accordance with a situation. In addition, even in a case inwhich a filter application unit is switched, the terminal apparatus canrecognize the switched application unit on the basis of a notificationfrom the base station. In other words, the terminal apparatus canrecognize a resource to which the filter is applied in accordance withthe switched filter application unit on the basis of a notification fromthe base station.

Note that, although the case in which the base station determines thefilter application unit has been focused on in the above-describedexample, a main agent that determines the filter application unit is notnecessarily limited to the base station. As a specific example, theterminal apparatus may determine the filter application unit. Note that,in that case, the terminal apparatus may notify the base station of theinformation indicating the determined filter application unit as partof, for example, RRC signaling or uplink control information (UCI).

(c) Case in which Filter Application Unit is Dynamically Determined

Next, the case in which a filter application unit is dynamicallydetermined will be described. In that case, for example, the basestation determines a filter application unit on the basis of apredetermined condition, i.e., a predetermined determination criterionfor determining a filter application unit. Note that, as information fordetermining a filter application unit, for example, the number ofsubcarriers to which a filter is applied, and the number of symbols (orthe number of sub-symbols) to which a filter is applied are exemplified.

Note that, as determination criteria for determining a filterapplication unit, there are the following examples, as in theabove-described case in which a filter application unit issemi-statically determined.

-   -   Bandwidth of the system    -   Feedback from the terminal apparatus on a communication quality    -   Retransmission request from the terminal apparatus    -   Position information of the terminal apparatus    -   Use application of the terminal apparatus (a request for a        communication quality from the terminal apparatus)    -   Request for switching of a filter application unit from the        terminal apparatus

In addition, as methods of the base station notifying the terminalapparatus of the information representing the filter application unit(i.e., information regarding a resource to which the filter is applied),there are also the following examples similarly to the above-describedcase in which a filter application unit is semi-statically determined.

-   -   Notifying as part of RRC signaling (RRC Message)    -   Notifying as part of system information    -   Notifying as part of DCI

In addition, the terminal apparatus may determine a filter applicationunit. In this case, the terminal apparatus may notify the base stationof information representing the determined filter application unit, forexample, as part of RRC signaling or uplink control information (UCI).

With the above-described configuration, the filter application unit canbe more flexibly switched in accordance with a situation. In addition,even in a case in which the filter application unit has been switched,the terminal apparatus can recognize the switched application unit onthe basis of a notification from the base station.

(5) Timing at which Filter Application Unit is Switched

Next, an example of a timing at which a filter application unit isswitched will be described. For example, although the base station mayperform switching of a filter application unit each time with respect todata to be transmitted, the base station may determine a timing at whichswitching is possible and switch the filter application unit on thebasis of the determination result.

As a timing at which the base station switches the filter applicationunit, there are the following examples.

-   -   Switching based on feedback from the terminal apparatus on a        communication quality    -   Switching at each predetermined timing (e.g., for one frame,        etc.)    -   Switching at a retransmission timing

That is, the base station may determine a timing at which a filterapplication unit is switched on the basis of the above-describedconditions and switch the filter application unit at the timing based onthe determination result.

In addition, as another example, the base station may notify theterminal apparatus that it is a timing at which the filter applicationunit can be switched on the basis of a determination result of thetiming at which the filter application unit is switched. In addition, ina case in which the notification of the timing at which the filterapplication unit can be switched is received from the base station, theterminal apparatus determines whether switching of the filterapplication unit is necessary. Then, in a case in which the terminalapparatus determines switching of the filter application unit to benecessary, the terminal apparatus notifies the base station of a requestfor switching of the filter application unit. In this case, the basestation may switch the filter application unit in accordance with therequest from the terminal apparatus.

Note that, as timings at which the terminal apparatus requests switchingof the filter application unit from the base station, there are thefollowing examples.

-   -   Issuing a notification in a case in which a measurement result        of a communication quality is a threshold value or lower    -   Issuing a notification in a case in which a decoding error        occurs

The example of a timing at which a filter application unit is switchedhas been described above. Note that an example of a flow of processesrelating to switching of a filter application unit will be separatelydescribed below.

(6) Flow of Processes

Successively, examples of flows of processes of the system according tothe present embodiment will be described with reference to FIG. 13 andFIG. 14 .

(a) Processes Relating to Determination of Filter Application Unit

First, an example of a flow of a series of processes relating todetermination of a filter application unit will be described withreference to FIG. 13 . FIG. 13 is a flowchart illustrating the exampleof the flow of the series of processes relating to determination of afilter application unit. Note that, in the present description, the basestation 100 will be assumed to determine a filter application unit.

First, the base station 100 (the communication processing unit 151)determines whether a filter for further limiting a frequency band widthto be used as a guard band is to be applied to a transmission signal(S101). In a case in which it is determined that a filter is not to beapplied (NO in S101), the base station 100 ends the series of processesrelating to determination of a filter application unit.

In addition, in a case in which it is determined that a filter is to beapplied (YES in S101), the base station 100 (the communicationprocessing unit 151) checks a minimum unit to which a filter is applied(S103). Note that a minimum unit to which a filter is applied is asdescribed above.

Next, the base station 100 (the communication processing unit 151)determines a filter application unit. Specifically, in a case in which afilter application unit is fixed (YES in S105), the base station 100applies a filter to the transmission signal in each unit in accordancewith the application unit on the basis of the application unit based ona specification (communication protocol) (S107).

In addition, in a case in which a filter application unit issemi-statically determined (NO in S105 and YES in S109), the basestation 100 (the communication processing unit 151) selects a filterapplication unit from predetermined candidates on the basis of apredetermined condition. Then, the base station 100 applies a filter tothe transmission signal in each unit in accordance with the selectedfilter application unit.

In addition, in a case in which a filter application unit is dynamicallydetermined (NO in S109), the base station 100 (the communicationprocessing unit 151) dynamically determines a filter application unit onthe basis of a predetermined condition. Then, the base station 100applies a filter to the transmission signal in each unit in accordancewith the determined filter application unit.

The example of the flow of the series of processes relating to thedetermination of the filter application unit has been described abovewith reference to FIG. 13 .

(b) Process Relating to Switching of Filter Application Unit

Next, an example of a flow of a series of processes relating toswitching of a filter application unit will be described with referenceto FIG. 14 . FIG. 14 is a flowchart illustrating the example of the flowof the series of processes relating to switching of a filter applicationunit. Note that, in the present description, the base station 100 willbe assumed to switch a filter application unit. That is, the main agentof the processes indicated by reference numerals S201 to S205 and S213in the drawing is the base station 100, and the main agent of theprocesses indicated by reference numerals S207 to S211 is the terminalapparatus 200.

First, the base station 100 (the communication processing unit 151)checks whether it is a timing at which a filter application unit can beswitched (S201). In a case in which it is not a timing at which a filterapplication unit can be switched (NO in S201), the series of processesends without performing switching of a filter application unit.

In addition, in a case in which it is a timing at which a filterapplication unit can be switched (YES in S201), the base station 100(the communication processing unit 151) checks whether it is a timing atwhich the switching of a filter application unit is necessary (S203). Ina case in which it is a timing at which switching of a filterapplication unit is necessary (YES in S203), the base station 100 (thecommunication processing unit 151) determines a filter application uniton the basis of a predetermined condition. Then, the base station 100(the notification unit 153) notifies the terminal apparatus 200 ofinformation relating to the determined filter application unit (S213).

On the other hand, in a case in which it is determined that it is not atiming at which switching of a filter application unit is necessary (NOin S203), the base station 100 (the notification unit 153) notifies theterminal apparatus 200 that the switching of a filter application unitis possible (S205). Upon receiving the notification, the terminalapparatus 200 (the communication processing unit 243) determines whethera request for switching of a filter application unit is to be made withrespect to the base station 100 on the basis of a predeterminedcondition (S207). Note that, in a case in which the terminal apparatus200 determines not to make a request for switching of a filterapplication unit (NO in S209), the series of processes ends withoutperforming switching of a filter application unit.

In addition, in a case in which it is determined to make a request forswitching of a filter application unit (YES in S209), the terminalapparatus 200 (the notification unit 245) notifies the base station 100of the request for switching of a filter application unit. Uponreceiving the notification, the base station 100 (the communicationprocessing unit 151) determines a filter application unit on the basisof the predetermined condition. Then, the base station 100 (thenotification unit 153) notifies the terminal apparatus 200 of theinformation regarding the determined filter application unit (S213).

In addition, the terminal apparatus 200 (the information acquisitionunit 241) receives the notification of the information regarding thefilter application unit from the base station 100. Accordingly, theterminal apparatus 200 (the communication processing unit 243) canrecognize the filter application unit to be applied to a signaltransmitted from the base station 100, and thus can correctly decode thesignal transmitted from the base station 100. In addition, the terminalapparatus 200 (the information acquisition unit 241) may apply thefilter to a signal to be transmitted to the base station 100 in anapplication unit in accordance with the information notified from thebase station 100. Accordingly, the base station 100 can correctly decodethe signal transmitted from the terminal apparatus 200.

The example of the flow of the series of processes relating to theswitching of the filter application unit has been described above withreference to FIG. 14 .

4. APPLICATION EXAMPLES

The technology according to the present disclosure is applicable to avariety of products. For example, the base station 100 may beimplemented as any type of evolved node B (eNB) such as a macro eNB or asmall eNB. A small eNB may be an eNB that covers a smaller cell than amacro cell, such as a pico eNB, a micro eNB, or a home (femto) eNB.Alternatively, the base station 100 may be implemented as another typeof base station such as a node B or a base transceiver station (BTS).The base station 100 may include a main body (which is also referred toas base station apparatus) that controls radio communication, and one ormore remote radio heads (RRHs) disposed in a different place from thatof the main body. In addition, various types of terminals describedbelow may operate as the base station 100 by temporarily orsemi-permanently executing the base station function. Moreover, at leastsome of components of the base station 100 may be implemented in a basestation apparatus or a module for the base station apparatus.

In addition, the terminal apparatus 200 may be implemented as, forexample, a mobile terminal such as a smartphone, a tablet personalcomputer (PC), a notebook PC, a portable game terminal, aportable/dongle type mobile router or a digital camera, or an onboardterminal such as a car navigation apparatus. In addition, the terminalapparatus 200 may be implemented as a terminal (which is also referredto as machine type communication (MTC) terminal) that performsmachine-to-machine

(M2M) communication. Further, at least some components of the terminalapparatus 200 may be implemented in modules (e.g., integrated circuitmodules each including one die) mounted on these terminals.

<4.1. Application Example Regarding Base Station>

(First Application Example)

FIG. 15 is a block diagram illustrating a first example of the schematicconfiguration of an eNB to which the technology according to the presentdisclosure can be applied. An eNB 800 includes one or more antennas 810and a base station apparatus 820. Each antenna 810 can be connected tothe base station apparatus 820 via an RF cable.

Each of the antennas 810 includes one or more antenna elements (e.g., aplurality of antenna elements included in an MIMO antenna), and is usedfor the base station apparatus 820 to transmit and receive radiosignals. The eNB 800 includes the plurality of antennas 810 asillustrated in FIG. 15 . For example, the plurality of antennas 810 maybe compatible with a plurality of respective frequency bands used by theeNB 800. Note that FIG. 15 illustrates the example in which the eNB 800includes the plurality of antennas 810, but the eNB 800 may also includethe one antenna 810.

The base station apparatus 820 includes a controller 821, a memory 822,a network interface 823, and a radio communication interface 825.

The controller 821 may be, for example, a CPU or a DSP, and operates thevarious functions of a higher layer of the base station apparatus 820.For example, the controller 821 generates a data packet from data insignals processed by the radio communication interface 825, andtransfers the generated packet via the network interface 823. Thecontroller 821 may bundle data from a plurality of base band processorsto generate the bundled packet, and transfer the generated bundledpacket. In addition, the controller 821 may have logical functions ofperforming control such as radio resource control, radio bearer control,mobility management, admission control, or scheduling. In addition, thecontrol may be executed in corporation with an eNB or a core networknode in the vicinity. The memory 822 includes a RAM and a ROM, andstores a program that is executed by the controller 821, and variouskinds of control data (e.g., terminal list, transmission power data,scheduling data, and the like).

The network interface 823 is a communication interface for connectingthe base station apparatus 820 to a core network 824. The controller 821may communicate with a core network node or another eNB via the networkinterface 823. In that case, the eNB 800 may be connected to a corenetwork node or another eNB through a logical interface (e.g., S1interface or X2 interface). The network interface 823 may also be awired communication interface or a radio communication interface forradio backhaul. In the case where the network interface 823 is a radiocommunication interface, the network interface 823 may use a higherfrequency band for radio communication than a frequency band used by theradio communication interface 825.

The radio communication interface 825 supports any cellularcommunication scheme such as Long Term Evolution (LTE) or LTE-Advanced,and provides radio connection to a terminal positioned in a cell of theeNB 800 via the antenna 810. The radio communication interface 825 cantypically include a baseband (BB) processor 826, an RF circuit 827, andthe like. The BB processor 826 may perform, for example,encoding/decoding, modulating/demodulating, multiplexing/demultiplexingand the like, and executes various kinds of signal processing of layers(such as L1, medium access control (MAC), radio link control (RLC), anda packet data convergence protocol (PDCP)). The BB processor 826 mayhave a part or all of the above-described logical functions instead ofthe controller 821. The BB processor 826 may be a memory that stores acommunication control program, or a module that includes a processor anda related circuit configured to execute the program. Updating theprogram may allow the functions of the BB processor 826 to be changed.In addition, the above-described module may be a card or a blade that isinserted into a slot of the base station apparatus 820. Alternatively,the above-described module may also be a chip that is mounted on theabove-described card or the above-described blade. Meanwhile, the RFcircuit 827 may include a mixer, a filter, an amplifier and the like,and transmits and receives radio signals via the antenna 810.

The radio communication interface 825 includes the plurality of BBprocessors 826, as illustrated in FIG. 15 . For example, the pluralityof BB processors 826 may be compatible with each of a plurality offrequency bands used by the eNB 800. In addition, the radiocommunication interface 825 includes the plurality of RF circuits 827,as illustrated in FIG. 15 . For example, the plurality of RF circuits827 may be compatible with respective antenna elements. Note that FIG.15 illustrates the example in which the radio communication interface825 includes the plurality of BB processors 826 and the plurality of RFcircuits 827, but the radio communication interface 825 may also includethe one BB processor 826 or the one RF circuit 827.

In the eNB 800 illustrated in FIG. 15 , one or more components (thetransmission processing unit 151 and/or the notification unit 153)included in the processing unit 150 described with reference to FIG. 4may be implemented in the radio communication interface 825.Alternatively, at least some of these components may be implemented inthe controller 821. As an example, a module that includes a part (e.g.,BB processor 826) or the whole of the radio communication interface 825and/or the controller 821 may be mounted in the eNB 800, and theabove-described one or more components may be implemented in the module.In this case, the above-described module may store a program for causingthe processor to function as the above-described one or more components(i.e., program for causing the processor to execute the operations ofthe above-described one or more components) and may execute the program.As another example, the program for causing the processor to function asthe above-described one or more components may be installed in the eNB800, and the radio communication interface 825 (e.g., BB processor 826)and/or the controller 821 may execute the program. As described above,the eNB 800, the base station apparatus 820, or the above-describedmodule may be provided as an apparatus that includes the above-describedone or more components, and the program for causing the processor tofunction as the above-described one or more components may be provided.In addition, a readable recording medium having the above-describedprogram recorded thereon may be provided.

In addition, in an eNB 830 illustrated in FIG. 15 , the radiocommunication unit 120 described with reference to FIG. 4 may beimplemented in the radio communication interface 825 (e.g., RF circuit827). In addition, the antenna unit 110 may be implemented in theantenna 810. In addition, the network communication unit 130 may beimplemented in the controller 821 and/or the network interface 823. Inaddition, the storage unit 140 may be implemented in the memory 822.

(Second Application Example)

FIG. 16 is a block diagram illustrating a second example of a schematicconfiguration of an eNB to which the technology according to the presentdisclosure can be applied. The eNB 830 includes one or more antennas840, a base station apparatus 850, and an RRH 860. Each antenna 840 maybe connected to the RRH 860 via an RF cable. In addition, the basestation apparatus 850 can be connected to the RRH 860 via a high speedline such as an optical fiber cable.

Each of the antennas 840 includes one or more antenna elements (e.g., aplurality of antenna elements included in an MIMO antenna), and is usedfor the RRH 860 to transmit and receive radio signals. The eNB 830includes the plurality of antennas 840 as illustrated in FIG. 16 . Forexample, the plurality of antennas 840 may be compatible with aplurality of respective frequency bands used by the eNB 830. Note thatFIG. 16 illustrates the example in which the eNB 830 includes theplurality of antennas 840, but the eNB 830 may include the one antenna840.

The base station apparatus 850 includes a controller 851, a memory 852,a network interface 853, a radio communication interface 855, and aconnection interface 857. The controller 851, the memory 852, and thenetwork interface 853 are the same as the controller 821, the memory822, and the network interface 823 described with reference to FIG. 15 .

The radio communication interface 855 supports any cellularcommunication scheme such as LTE or LTE-Advanced, and provides radiocommunication to a terminal positioned in the sector corresponding tothe RRH 860 via the RRH 860 and the antenna 840. The radio communicationinterface 855 can typically include a BB processor 856 and the like. TheBB processor 856 is similar to the BB processor 826 described withreference to FIG. 15 , except that the BB processor 856 is connected tothe RF circuit 864 of the RRH 860 via the connection interface 857. Theradio communication interface 855 includes the plurality of BBprocessors 856 as illustrated in FIG. 16 . For example, the plurality ofBB processors 856 may be compatible with a plurality of respectivefrequency bands used by the eNB 830. Note that FIG. 16 illustrates theexample in which the radio communication interface 855 includes theplurality of BB processors 856, but the radio communication interface855 may include the one BB processor 856.

The connection interface 857 is an interface for connecting the basestation apparatus 850 (radio communication interface 855) to the RRH860. The connection interface 857 may also be a communication module forcommunication in the above-described high speed line that connects thebase station apparatus 850 (radio communication interface 855) to theRRH 860.

The RRH 860 includes a connection interface 861 and a radiocommunication interface 863.

The connection interface 861 is an interface for connecting the RRH 860(radio communication interface 863) to the base station apparatus 850.The connection interface 861 may also be a communication module forcommunication in the above-described high speed line.

The radio communication interface 863 transmits and receives radiosignals via the antenna 840. The radio communication interface 863 maytypically include the RF circuit 864 and the like. The RF circuit 864may include a mixer, a filter, an amplifier and the like, and transmitsand receives radio signals via the antenna 840. The radio communicationinterface 863 includes the plurality of RF circuits 864 as illustratedin FIG. 16 . For example, the plurality of RF circuits 864 may becompatible with a plurality of respective antenna elements. Note thatFIG. 16 illustrates the example in which the radio communicationinterface 863 includes the plurality of RF circuits 864, but the radiocommunication interface 863 may include the one RF circuit 864.

In the eNB 830 illustrated in FIG. 16 , one or more components (thetransmission processing unit 151 and/or the notification unit 153)included in the processing unit 150 described with reference to FIG. 4may be implemented in the radio communication interface 855 and/or theradio communication interface 863. Alternatively, at least some of thesecomponents may be implemented in the controller 851. As an example, amodule that includes a part (e.g., BB processor 856) or the whole of theradio communication interface 855 and/or the controller 821 may bemounted in eNB 830, and the above-described one or more components maybe implemented in the module. In this case, the above-described modulemay store a program for causing the processor to function as theabove-described one or more components (i.e., a program for causing theprocessor to execute the operations of the above-described one or morecomponents) and may execute the program. As another example, the programfor causing the processor to function as the above-described one or morecomponents may be installed in the eNB 830, and the radio communicationinterface 855 (e.g., BB processor 856) and/or the controller 851 mayexecute the program. As described above, the eNB 830, the base stationapparatus 850, or the above-described module may be provided as anapparatus that includes the above-described one or more components, andthe program for causing the processor to function as the above-describedone or more components may be provided. In addition, a readablerecording medium having the above-described program recorded thereon maybe provided.

In addition, in the eNB 830 illustrated in FIG. 16 , the radiocommunication unit 120 described, for example, with reference to FIG. 4may be implemented in the radio communication interface 863 (e.g., RFcircuit 864). In addition, the antenna unit 110 may be implemented inthe antenna 840. In addition, the network communication unit 130 may beimplemented in the controller 851 and/or the network interface 853. Inaddition, the storage unit 140 may be implemented in the memory 852.

<4.2. Application Example Regarding Terminal Apparatus>

(First Application Example)

FIG. 17 is a block diagram illustrating an example of the schematicconfiguration of a smartphone 900 to which the technology of the presentdisclosure can be applied. The smartphone 900 includes a processor 901,a memory 902, a storage 903, an external connection interface 904, acamera 906, a sensor 907, a microphone 908, an input device 909, adisplay device 910, a speaker 911, a radio communication interface 912,one or more antenna switches 915, one or more antennas 916, a bus 917, abattery 918, and an auxiliary controller 919.

The processor 901 may be, for example, a CPU or a system on a chip(SoC), and controls functions of the application layer and another layerof the smartphone 900. The memory 902 includes a RAM and a ROM, andstores a program that is executed by the processor 901, and data. Thestorage 903 can include a storage medium such as a semiconductor memoryor a hard disk. The external connection interface 904 is an interfacefor connecting an external device such as a memory card or a universalserial bus (USB) device to the smartphone 900.

The camera 906 includes an image sensor such as a charge coupled device(CCD) or a complementary metal oxide semiconductor (CMOS), and generatesa captured image. The sensor 907 can include, for example, a group ofsensors such as a measurement sensor, a gyro sensor, a geomagneticsensor, and an acceleration sensor. The microphone 908 converts soundinput to the smartphone 900 to sound signals. The input device 909includes, for example, a touch sensor configured to detect touch onto ascreen of the display device 910, a keypad, a keyboard, a button, aswitch or the like, and receives an operation or an information inputfrom a user. The display device 910 includes a screen such as a liquidcrystal display (LCD) or an organic light-emitting diode (OLED) display,and displays an output image of the smartphone 900. The speaker 911converts sound signals output from the smartphone 900 to sound.

The radio communication interface 912 supports any cellularcommunication scheme such as LTE and LTE-Advanced, and executes radiocommunication. The radio communication interface 912 may typicallyinclude a BB processor 913, an RF circuit 914, and the like. The BBprocessor 913 may perform, for example, encoding/decoding,modulating/demodulating, multiplexing/demultiplexing and the like, andexecutes various kinds of signal processing for radio communication.Meanwhile, the RF circuit 914 may include a mixer, a filter, anamplifier and the like, and transmits and receives radio signals via theantenna 916. The radio communication interface 912 may also be a onechip module that has the BB processor 913 and the RF circuit 914integrated thereon. The radio communication interface 912 may includethe plurality of BB processors 913 and the plurality of RF circuits 914as illustrated in FIG. 17 . Note that FIG. 17 illustrates the example inwhich the radio communication interface 912 includes the plurality of BBprocessors 913 and the plurality of RF circuits 914, but the radiocommunication interface 912 may also include the one BB processor 913 orthe one RF circuit 914.

Further, in addition to a cellular communication scheme, the radiocommunication interface 912 may support another type of radiocommunication scheme such as a short-distance radio communicationscheme, a near field communication scheme, or a radio local area network(LAN) scheme. In that case, the radio communication interface 912 mayinclude the BB processor 913 and the RF circuit 914 for each radiocommunication scheme.

Each of the antenna switches 915 switches a connection destination ofthe antenna 916 between a plurality of circuits (e.g., circuits fordifferent radio communication schemes) included in the radiocommunication interface 912.

Each of the antennas 916 includes one or more antenna elements (e.g., aplurality of antenna elements included in an MIMO antenna), and is usedfor the radio communication interface 912 to transmit and receive radiosignals. The smartphone 900 may include the plurality of antennas 916 asillustrated in FIG. 17 . Note that FIG. 17 illustrates the example inwhich the smartphone 900 includes the plurality of antennas 916, but thesmartphone 900 may include the one antenna 916.

Further, the smartphone 900 may include the antenna 916 for each radiocommunication scheme. In that case, the antenna switches 915 may beomitted from the configuration of the smartphone 900.

The bus 917 connects the processor 901, the memory 902, the storage 903,the external connection interface 904, the camera 906, the sensor 907,the microphone 908, the input device 909, the display device 910, thespeaker 911, the radio communication interface 912, and the auxiliarycontroller 919 to each other. The battery 918 supplies power to therespective blocks of the smartphone 900 illustrated in FIG. 17 viafeeder lines that are partially illustrated as dashed lines in thefigure. The auxiliary controller 919 operates a minimum necessaryfunction of the smartphone 900, for example, in a sleep mode.

In the smartphone 900 illustrated in FIG. 17 , one or more components(the information acquisition unit 241, the communication processing unit243 and/or the notification unit 245) included in the processing unit240 described with reference to FIG. 5 may be implemented in the radiocommunication interface 912. Alternatively, at least some of thesecomponents may be implemented in the processor 901 or the auxiliarycontroller 919. As an example, a module that includes a part (e.g., BBprocessor 913) or the whole of the radio communication interface 912,the processor 901 and/or the auxiliary controller 919 may be mounted inthe smartphone 900, and the above-described one or more components maybe implemented in the module. In this case, the above-described modulemay store a program for causing the processor to function as theabove-described one or more components (i.e., a program for causing theprocessor to execute the operations of the above-described one or morecomponents) and may execute the program. As another example, the programfor causing the processor to function as the above-described one or morecomponents may be installed in the smartphone 900, and the radiocommunication interface 912 (e.g., BB processor 913), the processor 901and/or the auxiliary controller 919 may execute the program. Asdescribed above, the smartphone 900 or the above-described module may beprovided as an apparatus that includes the above-described one or morecomponents, and the program for causing the processor to function as theabove-described one or more components may be provided. In addition, areadable recording medium having the above-described program recordedthereon may be provided.

In addition, in the smartphone 900 illustrated in FIG. 17 , the radiocommunication unit 220 described, for example, with reference to FIG. 5may be implemented in the radio communication interface 912 (e.g., RFcircuit 914). In addition, the antenna unit 210 may be implemented inthe antenna 916. In addition, the storage unit 230 may be implemented inthe memory 902.

(Second Application Example)

FIG. 18 is a block diagram illustrating an example of the schematicconfiguration of a car navigation apparatus 920 to which the technologyof the present disclosure can be applied. The car navigation apparatus920 includes a processor 921, a memory 922, a global positioning system(GPS) module 924, a sensor 925, a data interface 926, a content player927, a storage medium interface 928, an input device 929, a displaydevice 930, a speaker 931, a radio communication interface 933, one ormore antenna switches 936, one or more antennas 937, and a battery 938.

The processor 921 may be, for example, a CPU or a SoC, and controls thenavigation function and another function of the car navigation apparatus920. The memory 922 includes a RAM and a ROM, and stores a program thatis executed by the processor 921, and data.

The GPS module 924 uses GPS signals received from a GPS satellite tomeasure the position (e.g., latitude, longitude, and altitude) of thecar navigation apparatus 920. The sensor 925 may include, for example, agroup of sensors such as a gyro sensor, a geomagnetic sensor, and abarometric sensor. The data interface 926 is connected to, for example,an in-vehicle network 941 via a terminal that is not illustrated, andacquires data such as vehicle speed data generated by the vehicle side.

The content player 927 reproduces content stored in a storage medium(e.g., CD or DVD) that is inserted into the storage medium interface928. The input device 929 includes, for example, a touch sensorconfigured to detect touch onto a screen of the display device 930, abutton, a switch or the like and receives an operation or an informationinput from a user. The display device 930 includes a screen such as anLCD or an OLED display, and displays an image of the navigation functionor content that is reproduced. The speaker 931 outputs the sound of thenavigation function or the content that is reproduced.

The radio communication interface 933 supports any cellularcommunication scheme such as LTE and LTE-Advanced, and executes radiocommunication. The radio communication interface 933 may typicallyinclude a BB processor 934, an RF circuit 935, and the like. The BBprocessor 934 may perform, for example, encoding/decoding,modulating/demodulating, multiplexing/demultiplexing and the like, andexecutes various kinds of signal processing for radio communication.Meanwhile, the RF circuit 935 may include a mixer, a filter, anamplifier and the like, and transmits and receives radio signals via theantenna 937. The radio communication interface 933 may also be a onechip module that has the BB processor 934 and the RF circuit 935integrated thereon. The radio communication interface 933 may includethe plurality of BB processors 934 and the plurality of RF circuits 935as illustrated in FIG. 18 . Note that FIG. 18 illustrates the example inwhich the radio communication interface 933 includes the plurality of BBprocessors 934 and the plurality of RF circuits 935, but the radiocommunication interface 933 may also include the one BB processor 934 orthe one RF circuit 935.

Further, in addition to a cellular communication scheme, the radiocommunication interface 933 may support another type of radiocommunication scheme such as a short-distance radio communicationscheme, a near field communication scheme, or a radio LAN scheme. Inthat case, the radio communication interface 933 may include the BBprocessor 934 and the RF circuit 935 for each radio communicationscheme.

Each of the antenna switches 936 switches a connection destination ofthe antenna 937 between a plurality of circuits (e.g., circuits fordifferent radio communication schemes) included in the radiocommunication interface 933.

Each of the antennas 937 includes one or more antenna elements (e.g., aplurality of antenna elements included in an MIMO antenna), and is usedfor the radio communication interface 933 to transmit and receive radiosignals. The car navigation apparatus 920 may include the plurality ofantennas 937 as illustrated in FIG. 18 . Note that FIG. 18 illustratesan example in which the car navigation apparatus 920 includes theplurality of antennas 937, but the car navigation apparatus 920 mayinclude the one antenna 937.

Further, the car navigation apparatus 920 may include the antenna 937for each radio communication scheme. In that case, the antenna switches936 may be omitted from the configuration of the car navigationapparatus 920.

The battery 938 supplies power to the respective blocks of the carnavigation apparatus 920 illustrated in FIG. 18 via feeder lines thatare partially illustrated as dashed lines in the figure. In addition,the battery 938 accumulates power supplied from the vehicle side.

In the car navigation apparatus 920 illustrated in FIG. 18 , one or morecomponents (the information acquisition unit 241, the communicationprocessing unit 243, and/or the notification unit 245) included in theprocessing unit 240 described with reference to FIG. 5 may beimplemented in the radio communication interface 933. Alternatively, atleast some of these components may be implemented in the processor 921.As an example, a module that includes a part (e.g., BB processor 934) orthe whole of the radio communication interface 933 and/or the processor921 may be mounted in the car navigation apparatus 920, and theabove-described one or more components may be implemented in the module.In this case, the above-described module may store a program for causingthe processor to function as the above-described one or more components(i.e., a program for causing the processor to execute the operations ofthe above-described one or more components) and may execute the program.As another example, the program for causing the processor to function asthe above-described one or more components may be installed in the carnavigation apparatus 920, and the radio communication interface 933(e.g., BB processor 934) and/or the processor 921 may execute theprogram. As described above, the car navigation apparatus 920 or theabove-described module may be provided as an apparatus that includes theabove-described one or more components, and the program for causing theprocessor to function as the above-described one or more components maybe provided. In addition, a readable recording medium having theabove-described program recorded thereon may be provided.

In addition, in the car navigation apparatus 920 illustrated in FIG. 18, the radio communication unit 220 described, for example, withreference to FIG. 5 may be implemented in the radio communicationinterface 933 (e.g., RF circuit 935). In addition, the antenna unit 210may be implemented in the antenna 937. In addition, the storage unit 230may be implemented in the memory 922.

In addition, the technology according to the present disclosure may alsobe implemented as an in-vehicle system (or a vehicle) 940 including oneor more blocks of the above-described car navigation apparatus 920, thein-vehicle network 941, and a vehicle module 942. That is, thein-vehicle system (or the vehicle) 940 may be provided as an apparatusthat includes the information acquisition unit 241, the communicationprocessing unit 243, and/or the notification unit 245. The vehiclemodule 942 generates vehicle-side data such as vehicle speed, enginespeed, or trouble information, and outputs the generated data to thein-vehicle network 941.

5. CONCLUSION

The embodiment of the present disclosure has been described in detailabove with reference to FIG. 1 to FIG. 18 . As described above, the basestation 100 according to the embodiment notifies the terminal apparatus200 of control information regarding a resource to which a filter forlimiting a width of a guard band in a frequency band to be used in radiocommunication is applied. More specifically, a filter application unitis determined with a resource element as a minimum unit. Then, the basestation 100 notifies the terminal apparatus 200 of, for example,information regarding the determined filter application unit.

In addition, in a case in which each of the base station 100 and theterminal apparatus 200 operates as a transmission apparatus, thetransmission apparatus applies a filter for limiting a width of a guardband to transmission data (i.e., a transmission signal) on the basis ofcontrol information regarding a resource to which the filter is applied.Then, the transmission apparatus transmits the filter-appliedtransmission data to an external apparatus serving as a transmissiondestination.

According to the system of the embodiment, a resource (i.e., filterapplication unit) to which a filter for limiting a width of a guard bandis applied can be adaptively selected or determined in accordance with atransmission/reception environment or a use case with theabove-described configuration. Accordingly, the filter can be applied tothe transmission data in a more preferable mode, and improvement inthroughput of the whole system is expected.

The preferred embodiment (s) of the present disclosure has/have beendescribed above with reference to the accompanying drawings, whilst thepresent disclosure is not limited to the above examples. A personskilled in the art may find various alterations and modifications withinthe scope of the appended claims, and it should be understood that theywill naturally come under the technical scope of the present disclosure.

Further, the effects described in this specification are merelyillustrative or exemplified effects, and are not limitative. That is,with or in the place of the above effects, the technology according tothe present disclosure may achieve other effects that are clear to thoseskilled in the art from the description of this specification.

Additionally, the present technology may also be configured as below.

(1)

An apparatus including:

a communication unit configured to perform radio communication; and

a control unit configured to perform control such that controlinformation regarding a resource to which a filter for limiting a widthof a guard band in a frequency band to be used in the radiocommunication is applied is transmitted to an external apparatus throughthe radio communication.

(2)

The apparatus according to (1), in which the control unit determines aunit to which the filter is applied with the resource as a minimum unitand performs control such that information regarding the unit istransmitted to the external apparatus through the radio communication asthe control information regarding the resource.

(3)

The apparatus according to (2), in which the unit is determined on abasis of a number of resources in at least one of a frequency directionand a time direction.

(4)

The apparatus according to any one of (1) to (3), including:

a storage unit configured to store the control information,

in which the control unit performs control such that the controlinformation stored in the storage unit is transmitted to the externalapparatus through the radio communication.

(5)

The apparatus according to (1), in which the control unit determines aresource to which the filter is applied on a basis of a predeterminedcondition.

(6)

The apparatus according to (5), in which the control unit determines aresource to which the filter is applied from a plurality of presetcandidates on the basis of the predetermined condition.

(7)

The apparatus according to (5) or (6), in which the control unitdetermines a resource to which the filter is applied after receiving arequest for a resource to which the filter is applied from the externalapparatus.

(8)

The apparatus according to any one of (5) to (7), in which the controlunit determines a resource to which the filter is applied in accordancewith at least one of feedback from the external apparatus on acommunication quality, a retransmission request from the externalapparatus, position information of the external apparatus, and a requestfor a communication quality from the external apparatus.

(9)

The apparatus according to any one of (1) to (8), in which the controlunit performs control such that information regarding a timing at whicha resource to which the filter is applied is switched is transmitted tothe external apparatus through the radio communication.

(10)

The apparatus according to (2) or (3), in which the control unitdetermines the unit to which the filter is applied on a basis of apredetermined condition.

(11)

The apparatus according to (10), in which the control unit determinesthe unit to which the filter is applied from a plurality of presetcandidates on the basis of the predetermined condition.

(12)

The apparatus according to (10) or (11), in which the control unitdetermines the unit to which the filter is applied after receiving arequest for the unit to which the filter is applied from the externalapparatus.

(13)

The apparatus according to any one of (10) to (12), in which the controlunit determines the unit to which the filter is applied in accordancewith at least one of feedback from the external apparatus on acommunication quality, a retransmission request from the externalapparatus, position information of the external apparatus, and a requestfor a communication quality from the external apparatus.

(14)

The apparatus according to any one of (2), 3, and 10 to (13), in whichthe control unit performs control such that information regarding atiming at which the unit to which the filter is applied is switched istransmitted to the external apparatus through the radio communication.

(15)

An apparatus including:

a communication unit configured to perform radio communication; and

an acquisition unit configured to acquire control information regardinga resource to which a filter for limiting a width of a guard band in afrequency band to be used in the radio communication is applied from anexternal apparatus through the radio communication.

(16)

The apparatus according to (15), including:

a control unit configured to perform control such that a request forswitching of a resource to which the filter is applied is transmitted tothe external apparatus through the radio communication in accordancewith a predetermined condition.

(17)

The apparatus according to (16), in which the control unit performscontrol such that the request is transmitted to the external apparatusthrough the radio communication in accordance with a quality of theradio communication.

(18)

The apparatus according to (16), in which the control unit performscontrol such that the request is transmitted to the external apparatusthrough the radio communication in accordance with a decoding result ofdata received from the external apparatus through the radiocommunication.

(19)

An apparatus including:

a communication unit configured to perform radio communication; and

a control unit configured to perform control such that, on a basis ofcontrol information regarding a resource to which a filter for limitinga width of a guard band in a frequency band to be used in the radiocommunication is applied, the filter is applied to transmission data andthe transmission data to which the filter has been applied istransmitted to an external apparatus through the radio communication.

(20)

A method including:

performing radio communication; and

performing control, by a processor, such that control informationregarding a resource to which a filter for limiting a width of a guardband in a frequency band to be used in the radio communication isapplied is transmitted to an external apparatus through the radiocommunication.

(21)

A method including:

performing radio communication; and

acquiring, by a processor, control information regarding a resource towhich a filter for limiting a width of a guard band in a frequency bandto be used in the radio communication is applied from an externalapparatus through the radio communication.

(22)

A method including:

performing radio communication; and

performing control, by a processor, such that, on a basis of controlinformation regarding a resource to which a filter for limiting a widthof a guard band in a frequency band to be used in the radiocommunication is applied, the filter is applied to transmission data andthe transmission data to which the filter has been applied istransmitted to an external apparatus through the radio communication.

REFERENCE SIGNS LIST

-   1 system-   10 cell-   100 base station-   110 antenna unit-   120 radio communication unit-   130 network communication unit-   140 storage unit-   150 processing unit-   151 communication processing unit-   153 notification unit-   200 terminal apparatus-   210 antenna unit-   220 radio communication unit-   230 storage unit-   240 processing unit-   241 information acquisition unit-   243 communication processing unit-   245 notification unit

The invention claimed is:
 1. An apparatus comprising: circuitryconfigured to perform radio communication; transmit to an externalapparatus through the radio communication control information regardinga resource to be used in the radio communication: select a filterapplication unit from a plurality of candidates, wherein each of theplurality of candidates comprises a subcarrier bandwidth and a symbollength, and the filter application unit represents a minimumtime-frequency unit to which a filter is applied; divide a bit streaminto a plurality of units, each of the plurality of units having a sizeof the selected filter application unit; apply the filter to each of theplurality of units to generate a plurality of filtered units; and addthe plurality of filtered units to generate a signal for transmission,wherein the control information is transmitted to the externalapparatus, and the control information is used by the external apparatusto set the width of a guard band around the signal.
 2. The apparatusaccording to claim 1, wherein the circuitry is further configured toperform control such that information regarding the filter applicationunit is transmitted to the external apparatus through the radiocommunication as the control information regarding the resource.
 3. Theapparatus according to claim 2, wherein the filter application unit isdetermined on a basis of a number of resources in at least one of afrequency direction and a time direction.
 4. The apparatus according toclaim 2, wherein the circuitry is further configured to determine theresource to filter on a basis of a predetermined condition.
 5. Theapparatus according to claim 4, wherein the circuitry is furtherconfigured to determine the resource from a plurality of presetcandidates in accordance with at least one of feedback from the externalapparatus on a communication quality, a retransmission request from theexternal apparatus, position information of the external apparatus, anda request for a communication quality from the external apparatus. 6.The apparatus according to claim 2, wherein the circuitry is furtherconfigured to perform control such that information is transmitted tothe external apparatus through the radio communication regarding atiming at which the filter application unit is switched.
 7. Theapparatus according to claim 1, comprising: a storage unit configured tostore the control information, wherein the circuitry is furtherconfigured to perform control such that the control information storedin the storage unit is transmitted to the external apparatus through theradio communication.
 8. The apparatus according to claim 1, wherein thecircuitry is further configured to perform control such that informationregarding a timing at which the resource which is filtered is switchedis transmitted to the external apparatus through the radiocommunication.
 9. The apparatus according to claim 1, wherein thecircuitry is further configured to determine an application unit inaccordance with at least one of feedback from the external apparatus ona communication quality, a retransmission request from the externalapparatus, position information of the external apparatus, and a requestfor a communication quality from the external apparatus.
 10. Theapparatus according to claim 1, wherein the circuitry is furtherconfigured to select the filter application unit on the basis of apredetermined condition.
 11. The apparatus according to claim 1, whereinthe information comprises a request from the external apparatus toswitch the filter to a different one of a plurality of filtercandidates.
 12. The apparatus according to claim 1, wherein theinformation comprises feedback from the external apparatus on acommunication quality.
 13. The apparatus according to claim 1, whereinthe filter comprises at least one of a Dolph Chebyshev filter and aNyquest filter.
 14. The apparatus according to claim 1, wherein thecontrol information is transmitted to the external apparatus as part ofa Radio Resource Control (RRC) signaling.
 15. An apparatus comprising:circuitry configured to perform radio communication; acquire controlinformation regarding a resource to be used in the radio communicationfrom an external apparatus through the radio communication; select afilter application unit from a plurality of candidates wherein each ofthe plurality of filter candidates comprises a subcarrier bandwidth anda symbol length, and the filter application unit represents a minimumtime-frequency unit to which a filter is applied; divide a bit streaminto a plurality of units, each of the plurality of units having a sizeof the selected filter application unit; apply the filter to each of theplurality of units to generate a plurality of filtered units; and addthe plurality of filtered units to generate a signal for transmission,wherein the control information is acquired from the external apparatus,and the control information is used by the apparatus to set the width ofa guard band around the signal.
 16. The apparatus according to claim 15,wherein the circuitry is further configured to: perform control suchthat a request for switching of the resource which is limited istransmitted to the external apparatus through the radio communication inaccordance with a predetermined condition.
 17. The apparatus accordingto claim 16, wherein the circuitry is further configured to performcontrol such that the request is transmitted to the external apparatusthrough the radio communication in accordance with a quality of theradio communication.
 18. The apparatus according to claim 16, whereinthe circuitry is further configured to perform control such that therequest is transmitted to the external apparatus through the radiocommunication in accordance with a decoding result of data received fromthe external apparatus through the radio communication.
 19. An apparatuscomprising: circuitry configured to perform radio communication; performcontrol such that, on a basis of control information regarding aresource to which a filter is applied for limiting a width of a guardband in a frequency band to be used in the radio communication, thefilter is applied to transmission data and the transmission data towhich the filter has been applied is transmitted to an externalapparatus through the radio communication; divide the transmission datainto a plurality of units; apply the filter to each of the plurality ofunits to generate a plurality of filtered units; and add the pluralityof filtered units to generate a signal for transmission, wherein thefilter comprises a filter application unit representing a minimumtime-frequency unit to which the filter is applied, wherein the controlinformation is received from the external apparatus, and the controlinformation is used by the apparatus to set the width of the guard bandaround the signal, wherein the filter application unit is selected bythe external apparatus from a plurality of candidates based oninformation received from the apparatus, and wherein the plurality ofcandidates are stored in a memory and each of the plurality ofcandidates comprises a subcarrier bandwidth and a symbol length.
 20. Amethod comprising: performing radio communication; acquiring, by aprocessor, control information regarding a resource to be used in theradio communication from an external apparatus through the radiocommunication; selecting a filter application unit from a plurality ofcandidates, wherein each of the plurality of candidates comprises asubcarrier bandwidth and a symbol length, and the filter applicationunit represents a minimum time-frequency unit to which a filter isapplied; dividing a bit stream into a plurality of units, each of theplurality of units having a size of the selected filter applicationunit; applying the filter to each of the plurality of units to generatea plurality of filtered units; and adding the plurality of filteredunits to generate a signal for transmission, wherein the controlinformation is transmitted to the external apparatus as part of a RadioResource Control (RRC) signaling, and the control information is used bythe external apparatus to set the width of a guard band around thesignal.